Cholera is a fatal, but treatable, disease that affects millions of people worldwide.

Each year, approximately 15 countries are affected by large-scale outbreaks.

This year, the number has almost doubled.

Right now, there are 29 active outbreaks worldwide while the vaccine is still in development.

Haiti is one of the worst affected countries.

Cholera was discovered here at the end of September and since then the spread of infection has skyrocketed, but the vaccine is not enough.

Many people only receive one dose instead of the two that provide long-term protection.

- We have some doses, but we are far from having doses for everyone, but instead have to prioritize especially vulnerable groups, says Mia Hejdenberg from Doctors without Borders.

There is a very limited number of manufacturers in the world that produce vaccines and this year the needs are simply too great.

Nurse: The outbreaks are different from before

Mia Hejdenberg is a nurse and has been responsible for two of the organization's cholera treatment centers during a previous cholera outbreak in Congo-Kinshasa.

She says that the outbreaks we see today differ significantly.

- In Congo-Kinshasa, cholera is epidemic, which means that there is always cholera in a community, she says.

- The population was so used to cholera that they arrived at the treatment center in time.

That meant no one died.

It is very different from what we see now in places where people are not as used to it.

Climate change causes cholera outbreaks

Worst affected, apart from Haiti, are Syria and Lebanon.

It is not known exactly why the outbreaks have become so large, but something that contributes to the spread of cholera is the consequence of climate change: drought or floods.

- Another thing that affects is population movements that are related to conflicts, says Mia Hejdenberg.

That this is so is because cholera often breaks out in situations of overcrowding and a lack of clean water, adequate waste disposal and proper toilets.

How do you see the future spread of cholera outbreaks?

- What we are seeing right now is clearly very worrying, says Mia Hejdenberg and continues:

- We are concerned that it is an increasing trend.